Motion Detection Devices Research Articles

Elastomeric Sensor-Triboelectric Nanogenerator Coupled System for Multimodal Strain Sensing and Organic Vapor Detection.

Stretchable, flexible sensors are one of the most critical components of smart wearable electronics and Internet of Things (IoT), thereby attracting multipronged research interest in the last decades. Following miniaturization and multicomponent development of several sensors in one could further propel the demand for wireless, multimodal platforms. Greener substitutes to conventional sensors that can operate in a self-powered configuration are highly desirable in terms of all-in-one sensor utilities. However, fabrication of composite-based ultrastretchable, self-powered sensors with multifunctionality, robustness, and conformability is still only partially achieved and, therefore, demands further investigation. In this work, we report a triboelectric nanogenerator (TENG)-based multifunctional strain and organic vapor sensor using cross-linked ethylene propylene diene monomer (EPDM) elastomer and conducting carbon black as active fillers in the presence of an ionic liquid. The resulting piezoresistive sensor demonstrates ultrahigh gauge factor (GF > 220k) and wide range strain sensitivity and is, therefore, suitable for subtle-to-high frequency motion detection devices. Supported by excellent triboelectric outputs (force sensitivity 0.5 V/N in the range of 50-300 N, maximum output voltage VOC ∼ 178 V, short circuit current ISC ∼ 18 μA, maximum power density 0.11 mW/cm2), the hybrid sensors offer remarkable mechanical toughness and seamless voltage generation under contact-separation, even after several thousand cycles of operations. Furthermore, the sensor substrates exhibited reproducible organic vapor-sensing behavior, with high responsivity of 1.92 and 1 for ethanol and acetone, respectively, under flowing vapor conditions. This work lays a strong foundation for developing a truly multimodal, TENG-based, self-powered organic vapor and strain sensors.

Sodium alginate supramolecular nanofibers in synergy with surface crack engineering to prepare tough and highly sensitive hydrogels

Soft and wet hydrogels often struggle to achieve both toughness and high sensitivity simultaneously, limiting their usefulness in flexible devices. To tackle this challenge, we devised a strategy that combines supramolecular sodium alginate nanofibers, utilizing Zr4+ as physical crosslinkers, with surface crack engineering via the micro-phase separation of polyaniline, to create a physically and chemically dual crosslinked polyacrylamide (PAM)/sodium alginate (SA)/polyaniline (PANI) hydrogel with exceptional toughness and high sensitivity. Owing to the supramolecular sodium alginate nanofibers, the dual crosslinked hydrogel exhibited a tensile strength of 0.391 MPa, an elongation at break of 568.9 %, and a toughness of 1.020 MJ/m3. The in-situ polymerized polyaniline layer, confined within the dense network, introduced micro-cracks onto the hydrogel surface, resulting in a high gauge factor of 11.4 for the fabricated hydrogel. Furthermore, integrating this hydrogel into a triboelectric nanogenerator transformed it into self-powered sensors capable of detecting external forces and generating various signals without power supply. These findings suggest that the developed hydrogel held great potential in diverse fields, including human motion detection, human-machine interaction, and wearable electronic devices.

Ultra-stretchable and anti-freezing ionic conductive hydrogels as high performance strain sensors and flexible triboelectric nanogenerator in extreme environments

Conductive hydrogels have shown promising applications in a variety of portable smart wearable electronics and flexible sensors due to their high flexibility, stretchability, adjustable mechanical properties and excellent electrical conductivity. However, most of the current hydrogel-based flexible strain sensors and portable triboelectric nanogenerator (TENG) generally suffer from low stretchability/flexibility, poor mechanical properties, weak low-temperature tolerance and low power output. Herein, a multifunctional ionic conductive hydrogel (PPAVC-BA) with ultra-stretchability (∼1750%), high transparency (85%), high electrical conductivity (13.7 mS/cm), and outstanding anti-freezing properties (below −80°C without freezing). The strain sensor assembled from the PPAVC-BA hydrogel shows high sensitivity (GF=4.43) and ultra-wide sensing detection range (0%-1100%) as well as fast response time. Based on these properties, the PPAVC-BA hydrogel strain sensor can accurately recognize different joint movements of the human body as well as weak muscle beats. In addition, the PPAVC-BA hydrogel-based TENG (PPAVC-BA-TENG) exhibits excellent electrical output performance, with an open circuit voltage (Voc) of about 420 V, a short circuit current (Isc) of 23 μA, a short-circuit transfer charge (Qsc) of 112 nC and a maximum power density of 2246.03 mW/m2, which allows it to power small electronic devices. This PPAVC-BA-TENG also shows outstanding tensile performance and can output stable electrical signals at 200% strain. Impressively, the PPAVC-BA-TENG exhibits good electrical output performance even at low temperature of −50°C and high temperature of 80°C. The flexible strain sensors and stretchable TENG for high performance and multifunctionality reported in this work provide viable references in the development of motion detection, energy harvesting and self-powered electronic devices.

Self-healing flexible strain sensor fabricated through 3D printing template sacrifice for motion monitoring with enhanced healing and mechanical performance

With the advancements in flexible materials and information technology, flexible sensors are becoming increasingly pervasive in various aspects of life and production. They hold immense potential for further development in areas such as motion detection, electronic skin, soft robots, and wearable devices. Aminopropyl-terminated polydimethylsiloxane (PDMS) was used as the raw material, while a diisocyanate reagent served as the cross-linking agent for the polymerization reaction, which involved the introduction of ureido groups, containing N–H and C=O bonds, into the long siloxane chain. The dynamic hydrogen bonding between the clusters completes the self-healing of the material. Using 1-[3-(trimethoxysilyl)propyl]urea as a grafting agent, the urea groups are introduced into graphene oxide and carbon nanotubes (CNTs) as conductive fillers. Subsequently, a flexible polymer is used as the substrate to prepare conductive flexible self-healing composites. By controlling the amount of conductive fillers, flexible strain materials with varying sensitivities are obtained. Design the structure of the flexible strain sensor using three-dimensional (3D) modeling software with deposition printing method.

Xanthan gum toughen ionically conductive hydrogels for flexible and artificial epidermis sensors with multifunctionality and self-healability

Conductive hydrogels that possess hydrophobic interaction have gained much attention in fields like strain sensors, soft robotics, tissue engineering, human-machine interaction, and biomedical sensors due to their excellent stretchability and effective energy dissipation mechanism. However, their use is limited due to poor mechanical performance, low sensing ability, lack of response time, and deficiency of self-healing capability. To overcome these limitations, acrylamide-co-butylacrylate/xanthan gum-based hydrophobically associated conductive hydrogels were designed. Amphiphilic sodium dodecyl sulfate was employed both as a cross-linker and a micelle-forming agent, while LiCl make the hydrogel as an ionic conductive material. The obtained hydrogels show fracture stress and fracture strain of 661kPa and 1100% respectively. The measured conductivity was 0.21Sm−1 and the strain sensing of the designed hydrogel reached up to 800%. Similarly, the designed hydrogels show remarkable sensitivity (Gauge factor = 28.8 at an applied strain of 800%) which is useful in the detection of a wide range of human motions. Finger, wrist, elbow, and knee joint movement can be easily detected with these hydrogels. Furthermore, the hydrogel can detect speaking, facial expressions, and pressure sensing. The designed hydrogels showed an excellent response and recovery time of 0.15 s and 0.13 s respectively. During multiple stretching and un-stretching cycles for 140 s, the designed hydrogels show continuous linear response without any current drop or fracture. Therefore the as-fabricated hydrogel presents a novel opportunity for its application in various fields such as flexible conductive material, strain sensors, human motion detection devices, and tissue engineering.

Cold-resistant, highly stretchable ionic conductive hydrogels for intelligent motion recognition in winter sports.

Conductive hydrogels have attracted much attention for their wide application in the field of flexible wearable sensors due to their outstanding flexibility, conductivity and sensing properties. However, the weak mechanical properties, lack of frost resistance and susceptibility to microbial contamination of traditional conductive hydrogels greatly limit their practical application. In this work, multifunctional polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC)/poly(acrylamide-co-1-vinyl-3-butylimidazolium bromide) (P(AAm-co-VBIMBr)) (PCPAV) ionic conductive hydrogels with high strength and good conductive, transparent, anti-freezing and antibacterial properties were constructed by introducing a network of chemically crosslinked AAm and VBIMBr copolymers into the base material of PVA and CMC by in situ free radical polymerization. Owing to the multiple interactions between the polymers, including covalent crosslinking, multiple hydrogen bonding interactions, and electrostatic interactions, the obtained ionic conductive hydrogels exhibit a high tensile strength (360.6 kPa), a large elongation at break (810.6%), good toughness, and fatigue resistance properties. The introduction of VBIMBr endows the PCPAV hydrogels with excellent transparency (∼92%), a high ionic conductivity (15.2 mS cm-1), antimicrobial activity and good flexibility and conductivity at sub-zero temperatures. Notably, the PCPAV hydrogels exhibit a wide strain range (0-800%), high strain sensitivity (GF = 3.75), fast response, long-term stability, and fantastic durability, which enable them to detect both large joint movements and minute muscle movements. Based on these advantages, it is believed that the PCPAV-based hydrogel sensors would have potential applications in health monitoring, human motion detection, soft robotics, ionic skins, human-machine interfaces, and other flexible electronic devices.

MXene/PPy@PDMS sponge-based flexible pressure sensor for human posture recognition with the assistance of a convolutional neural network in deep learning

The combination of flexible sensors and deep learning has attracted much attention as an efficient method for the recognition of human postures. In this paper, an in situ polymerized MXene/polypyrrole (PPy) composite is dip-coated on a polydimethylsiloxane (PDMS) sponge to fabricate an MXene/PPy@PDMS (MPP) piezoresistive sensor. The sponge sensor achieves ultrahigh sensitivity (6.8925 kPa−1) at 0–15 kPa, a short response/recovery time (100/110 ms), excellent stability (5000 cycles) and wash resistance. The synergistic effect of PPy and MXene improves the performance of the composite materials and facilitates the transfer of electrons, making the MPP sponge at least five times more sensitive than sponges based on each of the individual single materials. The large-area conductive network allows the MPP sensor to maintain excellent electrical performance over a large-scale pressure range. The MPP sensor can detect a variety of human body activity signals, such as radial artery pulse and different joint movements. The detection and analysis of human motion data, which is assisted by convolutional neural network (CNN) deep learning algorithms, enable the recognition and judgment of 16 types of human postures. The MXene/PPy flexible pressure sensor based on a PDMS sponge has broad application prospects in human motion detection, intelligent sensing and wearable devices.

Wireless Human Motion Detection with a Highly Sensitive Wearable Pressure Sensing Technology

AbstractWireless flexible sensing devices using inductive‐capacitive (LC) resonator‐enabled transmission technologies are attractive in the areas of human motion detection, health inspection, and implantable medical devices. However, challenges remain in LC‐based wireless sensing devices, including low device sensitivity/resolution and slow signal readout speed based on sweeping excitation frequencies. Herein, an LC resonator‐based wireless pressure sensing technology (LC‐WPS) is proposed for flexible contact pressure measurements in a real‐time manner. It includes a fully flexible passive LC pressure sensor and a signal‐reading circuit for wireless communication with the sensor and real‐time data processing. The passive sensor detects external pressure by the changes in resonant frequency. Importantly, by optimizing the design of the LC resonator in the sensor, the LC‐WPS converts the pressure‐dependent resonant frequency into circuit output voltage to a great extent, achieving a high sensitivity (1.23 × 10−2 kPa−1) and resolution (54 Pa) within a pressure range of 0–15 kPa. In addition, the LC‐WPS utilizes a single operating frequency (i.e., 13.56 MHz) instead of sweeping the operating frequencies to identify the sensor resonant frequency, featuring fast and real‐time data analysis and processing. Real‐time monitoring of human motions, such as laryngeal movement, neck bending and wrist rotation, is demonstrated, verifying the applicability of the LC‐WPS in the fields of wearable medical care and sports biomechanics.

Nanocomposite hydrogels for strain sensing based on optical and electrical signals: a review.

Unlike metals, ceramics, or plastics, hydrogels are semi-solid, hydrophilic polymer networks with high water content. Embedding nanostructures or nanomaterials into hydrogels can impart special properties to the composites, such as anisotropy, optical or electrical properties. With the development of nanomaterials and advanced synthetic methods, nanocomposite hydrogels have attracted growing research interest in recent years due to their desirable mechanical properties, optical/electrical functions, reversibility, stimulus sensitivity, and biocompatibility. They have opened up a broad range of applications as stretchable strain sensors in mapping of strain distributions, motion detection, health-monitoring, and flexible skin-like devices. This minireview summarizes the recent developments in nanocomposite hydrogels as strain sensors based on optical and electrical signals. The strain sensing performances and their dynamic properties are discussed. Appropriate embedding of nanostructures or nanomaterials in hydrogels and engineering of interactions between nanomaterials and polymer networks can yield significant improvements in the performance of strain sensors.

Retracted: Design of Motion Detection Device in Sports Based on Deep Learning of Internet of Things.

[This retracts the article DOI: 10.1155/2022/2613318.].

Research and application of nuclear fuel embedded intelligent security monitoring technology

Electricity is the foundation of the entire national economy, and nuclear power has become an important part of the power system with its unique advantages. The main process of nuclear power is the process of the nuclear fuel cycle, including the source and preparation of nuclear fuel, nuclear power plants and nuclear spent fuel processing. In the whole process, nuclear safety is the top priority and the key to the sustainable development of nuclear power. In this paper, aiming at the objective reality of high security risk and strict security requirements for nuclear fuel storage used in nuclear power, based on the analysis of nuclear fuel radiation characteristics and safety monitoring requirements, a nuclear fuel embedded system is designed from the aspects of system overall, software, hardware, data processing, etc. Security intelligent monitoring system. The system uses MCU as the control core, is equipped with motion detection and electronic seal devices, and realizes alarm functions such as identity authentication, unauthorized movement, and illegal unpacking real-time monitoring. Experiments and use show that the system can be easily integrated, installed and deployed on the nuclear fuel packaging container, and the operation is stable and reliable, which effectively promotes the steady improvement of the operating efficiency and operating quality of the nuclear energy system.

A 3D printable, highly stretchable, self-healing hydrogel-based sensor based on polyvinyl alcohol/sodium tetraborate/sodium alginate for human motion monitoring

Self-healing hydrogels have great application potential in the field of bio-sensors due to their self-healing, flexibility and excellent tensile properties. However, most hydrogel-based sensors are processed by template method, which is unable to fabricate complex three-dimensional (3D) structures, and limits the development of hydrogel-based sensor devices. A simple yet efficient one-pot method was proposed to fabricate polyvinyl alcohol/sodium tetraborate/sodium alginate hydrogel inks (SPB), also a fabricating process of self-healing hydrogel based on 3D printing technology has been proposed. The SPB hydrogel rapidly healed (<30 s) at room temperature, while its mechanical properties and conductivity also recovered quickly after healing. Besides, it could be used as wearable strain sensors, whose high stretchability (>2800 % strain) and sensitivity (gauge factor: 18.56 at 2000 % strain) could not only detect very large stretch deformations, but also detect the tiny pressure changes in the human body, such as finger flexion, knee flexion, and respiration. This study provides a method for the rapid fabrication of complex-structured hydrogel-based sensors, which is helpful for the hydrogel-based sensor applications in human motion detection and wearable devices.

Pilot trial of a technology assisted treatment for trichotillomania

The present study examined the usability, acceptability, feasibility, and preliminary efficacy of a prototype wrist-worn motion detection device and accompanying mobile app, developed by HabitAware®, as a system for delivering self-administered Habit Reversal Training (HRT). As an exploratory aim, the effect of the device and HRT app combination was compared to a reminder bracelet. The pilot trial included 15 adults with trichotillomania who interacted with the device and app system (n = 10) or reminder bracelet (n = 5) for 4 weeks. Participants in the device and app condition reported high usability, acceptability, and perceived efficacy of the system. The device and HRT app combination reduced hair pulling severity. Individuals in the reminder bracelet condition also showed a significant improvement in hair pulling. A future efficacy study with a larger sample size, longer timeframe, and improved gesture detection algorithm is warranted.

Development of a Smart Motion Detection Device for Home and Office Security Applications

Abstract: The aim of this paper is to develop, implement and test an effective and practical working solution to a smart motion detector for LPWAN technologies using appropriate software and hardware platform. The smart motion detection system consists of a Raspberry Pi, an LCD display, PIR sensors, and wires. The hardware design collaborates with Python programming by being installed on a Raspberry Pi, and it is a key function to detect who is entering a room. The proposed smart motion detector will be able to detect whether a person is leaving or entering a room by analyzing signals from multiple motion sensors. The research carried out a comparative analysis of LoRA, SigFox, NB-IOT Low Power Wide Area Network technologies which include the principle of operation, characteristics, hardware, and make recommendation for the most suitable technology. The remote status update function implementation was done where the system sends the motion events to the cloud over a wireless interface using MQTT protocol. The evaluation which was based on extensive simulation demonstrated the detection of each sensor. Keywords: Smart motion detector, Raspberry pi, Python coding, PIR sensors, LPWAN technologies

Design of Motion Detection Device in Sports Based on Deep Learning of Internet of Things.

With the improvement of people's income levels in recent years, people have gradually begun to pay more attention to health, and the number of exercise and fitness people has increased year by year. People are gradually willing to pay for sports and fitness, increase sports consumption, and promote the development of the sports and fitness industry. This article aims to study the deep learning based on the Internet of things to make people aware of the importance of sports. Not loving sports is a major problem that contemporary people need to overcome. This article proposes how to design a motion detection device in sports based on deep learning of the Internet of things. Based on the calculation of the economic volume of the deep learning of the Internet of things and the questionnaire survey method, it can be seen that, in today's globalization, although everyone knows the importance of sports, they are unwilling to practice it and would rather spend more time on the Internet. The experimental results of this article show that more than 50% of college students are very interested in sports and fitness, but the actual use is less than 30%, which is not optimistic. In social surveys, this number will be even lower, with only 14% of people interested in sports. Big data is like a “double-edged sword.” It not only displays the user's exercise data in front of everyone through the built-in sensors of the mobile phone, but also manages their physical condition through these. How to use the strengths of sports applications at the same time properly disposing of private information is a part of the next development of sports applications that must be faced.

A novel PANI/SEBS film/fiber large deformation conductive elastomer with rapid recovery of resistance

A novel polyaniline (PANI)/poly(styrene-ethylene-butadienestyrene) (SEBS) film/fiber composite was developed via the electro-spinning and solution casting method. The structure of continuous conductive fiber was successfully constructed on the surface of the PANI/SEBS film. In comparison with the simple PANI/SEBS film, this unique continuous conductive fiber structure can improve the conductivity of the composite, reduce the resistance recovery time by 89% at the maximum, and significantly improve the hysteresis effect. This material may be applied as the flexible strain sensor for manufacturing human motion detection devices.

Aplikasi Sensor Passive Infra-Red (PIR) untuk Meningkatkan Keselamatan Pekerja pada Mesin-Mesin Produksi Industri

This research of literature study discusses about the function and application of infrared sensor-based motion detection devices for work safety on industrial cam machinery.This device was designed to assist the industry in preventing the work accidents that occur due to hazardous industrial machinery. The detector uses a PIR (Passive Infra-Red) sensor as a motion detector of the human limbs. On its application, PIR sensor is placed on a specific side of the machine. Then, the system will provide an automatic cut-off alarms on the machine when a person crosses the fabric area that has been detected by the sensor. It was expected that this way will protect the manpower from the occurrence of work accidents which are caused by dangerous industrial machines. With the implementation of this infrared sensor design, the analysis of hazardous machinery is becoming increased so that this infrared sensor based working security system is growing and easier for shaping in many designs.

Numerical Optimization Methods for Metasurfaces

AbstractIn recent years, metasurfaces have emerged as revolutionary tools to manipulate the behavior of light at the nanoscale. These devices consist of nanostructures defined within a single layer of metal or dielectric materials, and they offer unprecedented control over the optical properties of light, leading to previously unattainable applications in flat lenses, holographic imaging, polarimetry, and emission control, amongst others. The operation principles of metaoptics include complex light–matter interactions, often involving insidious near‐field coupling effects that are far from being described by classical ray optics calculations, making advanced numerical modeling a requirement in the design process. In this contribution, recent optimization techniques used in the inverse design of high performance metasurfaces are reviewed. These methods rely on the iterative optimization of a Figure of Merit to produce a final device, leading to freeform layouts featuring complex and non‐intuitive properties. The concepts in numerical inverse designs discussed herein will push this exciting field toward realistic and practical applications, ranging from laser wavefront engineering to innovative facial recognition and motion detection devices, including augmented reality retro‐reflectors and related complex light field engineering.

The Design of One-Dimensional Motion and Two-Dimensional Motion Learning Media Using Digital Camera and Tracker-Based Air Track

This research describes the results of the development of 2D air track tools designed for one and two-dimensional motion experiments with small frictional forces. Friction is minimized by using wind gusts through small holes made in all parts of the runway. Motion detection devices used are digital cameras and trackers. Digital cameras are used to record the motion of objects on a platform in the form of video with a specific frame-rate. Tracker is used to analyzing videos that contain information about object motion. This tool has been tested on one-dimensional motion, that is, an object that slides over an inclined plane and two-dimensional motion in the case of a collision of two objects. In the case of one-dimensional position graphs against time can be displayed, the instantaneous velocity and average and acceleration can be accurately determined. In the case of the collision of two objects, the position graph against time can also be displayed for each object before and after the collision. The velocity vector can be determined accurately so that the law of conservation of momentum and kinetic energy can be verified. One and two-dimensional motion are the concepts that underlie almost all other concepts in physics. Therefore one and two-dimensional motion experiments are important to build students’ experiences of the concept. Thus 2D air track platform based on digital cameras and Tracker software can be used as a physics learning media on motion kinematics materials that can display various kinematics graphs so that information about motion is complete.

Hollow-structured MXene-PDMS composites as flexible, wearable and highly bendable sensors with wide working range

Although versatile piezoresistive pressure sensors show a great potential as human motion detection and wearable smart devices, it is still an issue to widen their working range and enhance their sensitivity. Herein, hollow-structured MXene-polydimethylsiloxane composites (MPCs) are fabricated by utilizing nickel foam as the three-dimensional substrate for dip-coating of MXene sheets followed by infiltrating of polydimethylsiloxane and etching of the nickel foam substrate. The resultant MPC performs a wide working range with bending angles of 0° to 180°, an excellent long-term reliability up to 1000 cycles under the bending angles of 15°, 30° and 150°, and a stable durability with a bending angle of 30° in a frequency range from 0.05 to 2 Hz as a bendable piezoresistive pressure sensor, which is attributed to the formation of dense conduction paths due to the interconnection of MXene sheets during the deformation of MPC. The sensor also exhibits an extremely low detection limit of 10 mg for pressure detection. Interestingly, the slippage of adjacent MXene sheets is beneficial for monitoring slight vibration of equipments and detecting subtle human motions. Thus, the MPC sensor could be applied for stereo sound and ultrasonic vibration monitoring, swallowing, facial muscle movement, and various intense motion detections, demonstrating its great potential as wearable smart devices.